The personal computer industry has witnessed the emergence of two competing operating systems--Macintosh Operating System (MAC OS) and Microsoft Disk Operating System/Windows (DOS). Not only is the software for each operating system incompatible with the other operating system, but also the file formats employed by the operating systems are incompatible. As is described more fully below, the differences in file formats has created a hindrance to the distribution of popular software programs. Briefly, a disk formatted for use by a MAC OS based computer cannot be read by all DOS based computers and vice-versa. As a result, separate media must be used to distribute software for each operating system. That is, until recently, a single disk would have had to contain information that was readable by either a MAC OS based computer or a DOS based computer, but could not contain both.
A particularly important example of the difficulties created by the disparate file formats is related to software distribution. Currently, a popular software distribution technique is to provide a user with a copy of a software program on a disk. The term "disk" as used herein refers to magnetic disks, CD-ROMs and the like. Generally, the disks are packaged in shrink wrapped boxes and supplied either alone or along with a piece of computer equipment that requires additional software support. Because the operating systems are incompatible, multiple versions of a software program must be created in order for a particular program to support multiple operating systems. Multiple software program versions force a compromise in software distribution techniques. One distribution option available is to provide two sets of disks in a single package--one set for each operating system version of a software program. However, such an option unnecessarily increases the cost of distribution by including an unwanted and unused set of disks with every package. Alternatively, each package could contain a set of disks having a software program version compatible with only one operating system. Two different packages would then be required--one for each operating system. Unfortunately, with this second option, the distributor must determine in advance the appropriate quantity of packages to make and stock for each operating system. This second option also increases cost by creating inventory management problems. For example, inaccurately determining the quantity of each version of software program to stock could result in insufficient inventory for one version or the other.
Even if a single format that is readable by both operating systems is available, a separate limitation has been caused by the capacity of the distribution media. Until recently, program sizes have outstripped the capacities of one of the most common forms of distribution media--floppy disks. For example, distribution via conventional floppy disks (e.g., 1.44 Megabytes) requires multiple disks to store a single software program. Furthermore, because each operating system requires a different version of a software program, even if the same floppy disks were readable by both DOS and MAC OS based computers, both software program versions would not fit on a single floppy disk. As a result, separate disks, one for each operating system version, would still be required. However, with the advent of higher capacity media, such as the IOMEGA ZIP cartridge, it has become possible to store two different versions of a software program on a single disk.
The applicants have recognized some of the capabilities offered by the increased storage capacity of the IOMEGA ZIP cartridge and have devised a technique for dividing a single disk between MAC OS and DOS and formatting each portion accordingly. Significantly, a DOS version of a software program can be stored on the DOS portion of the disk, and a MAC OS version of a program can be stored on the MAC portion of the disk. However, the technique employed has had the drawback of requiring the distribution of a separate conventional floppy disk for each operating system along with the dual-format disk. Thus, for example, a user desiring to read the MAC OS software from a dual-format ZIP cartridge would first insert a floppy disk and run a program to enable it to read the MAC OS formatted portion of the disk. Once the MAC OS portion was read, the DOS portion of the disk would be deleted and made available to MAC OS. A similar process was required on a DOS based computer.
Applicants have recognized that a method of reducing the number of distribution disks needed to distribute a typical software program would provide significant economic advantages when aggregated over a large volume of distribution disks required. Thus, there is a need for an improved dual-format disk and installation method that would reduce the number of distribution disks required for a typical software program.